1. Field of the Invention
The present invention relates to a treble-bass coaxial loudspeaker, and more particularly to a treble-bass coaxial loudspeaker with long life for use.
2. Description of Related Art
With reference to FIG. 7, a treble-bass coaxial loudspeaker is formed as a single speaker body capable of generating treble and bass sounds at the same time. The treble-bass coaxial loudspeaker comprises:
an inverted conical frame 60 having a top side, wherein the top side of the inverted conical frame 60 forms a circular opening 61 and a bass resonance assembly is mounted under the inverted conical frame 60, wherein the bass resonance assembly from top to bottom comprises a wave damping annular board 62, a top yoke 63, a magnet 64 and a bottom yoke 65; wherein a middle portion of the magnet 64 forms a through-hole for a middle convex cylinder 651 of the bottom yoke 65 to penetrate upwardly and to be fastened;
a bass resonance drumhead 66 having an upper edge, wherein the bass resonance drumhead 66 is in an inverted conical shape, wherein the upper edge of the bass resonance drumhead 66 is mounted to an inner edge of the circular opening 61 of the inverted conical frame 60, wherein a bottom end of the bass resonance drumhead 66 forms a center opening to align with the through-hole of the magnet 64 and to be fastened to the wave damping annular board 62;
a central shaft 67 having a bottom, wherein the bottom of the central shaft 67 penetrates downward from the circular opening 61 of the inverted conical frame 60 through the central opening of the bass resonance drumhead 66 and the wave damping annular board 62, wherein the central shaft is fastened to the top of the middle convex cylinder 651 of the bottom yoke 65 by a screw 68 downward from the bottom surface of the middle convex cylinder 651 of the bottom yoke 65 through the middle convex cylinder 651 and the central shaft 67, wherein the central shaft 67 is fastened to the middle convex cylinder 651; and
a treble resonance assembly 70 comprising a treble resonance chip 71 and a treble resonance drumhead 72, wherein the bottom end of the treble resonance chip 71 is mounted at the top of the central shaft 67, wherein the treble resonance drumhead 72 is mounted on the top surface of the treble resonance chip 71. The treble resonance drumhead 72 is also in an inverted conical shape.
The central shaft 67 of the above treble-bass coaxial loudspeaker is penetratingly mounted into the bass loudspeaker central shaft. The treble resonance assembly 70 is mounted at the top surface of the treble-bass coaxial loudspeaker to generate treble sounds from the treble resonance drumhead 72 and generate bass sounds from the bass resonance drumhead 66 respectively. However, the treble quality of the coaxial loudspeaker is poor.
Therefore, an improved treble-bass coaxial loudspeaker is provided as shown in FIG. 8. The loudspeakers' structures are mostly the same in FIG. 7 and FIG. 8. The main difference between FIG. 7 and FIG. 8 is that there is no central shaft in FIG. 8. A top edge of the treble resonance drumhead 72a is fastened to the bass resonance drumhead 66. A blocking space is formed between the bass resonance drumhead 66 and the treble resonance drumhead 72a. The treble resonance chip 71 is mounted in the blocking space. The top surface of the treble resonance chip 71 is adhesive to the bottom end of the treble resonance drumhead 72a. The treble resonance chip 71 is suspended above the bottom surface of the treble resonance drumhead 72a to decrease the sonic resonance obstruction produced by the treble resonance chip 71 and to improve the treble quality.
Although the coaxial loudspeaker owns better treble quality, the treble resonance chip is only adhesively suspended to the bottom end of the treble resonance drumhead. Therefore, when the bass resonance drumhead vibrates, the air turbulence of the blocking space makes the treble resonance chip fall down easily from the treble resonance drumhead.